Into the Cave
by TimeLadyLoony
Summary: Sirius and Regulus were going to the cave together. Of course, they didn't tell anyone about this. Sirius wasn't sure it was a good idea. Part 2 go the Asking fo Help series.


**Into the Cave**

 **Fandom:** Harry Potter

 **Characters:** Sirius Black, Regulus Black

 **Warning:** None

* * *

The wind whipped at Sirius' face, and he wrinkled his nose, sending a doubtful glance at Regulus.

"Are you sure it's here?" he asked. "It's the middle of nowhere."

"I'm sure," Regulus answered, and he looked down at the house-elf with them. "Right Kreacher?"

Kreacher nodded quickly, and Regulus turned to Sirius, raising an eyebrow that probably meant "see?".

"I don't know why you had to bring him along," he said. "It's not like we need him."

"We do, actually. He was the only one who knew where to go. Not to mention, the whole place is covered with anti Apparition charms. Kreacher, as a house-elf, can bypass them. He's our only way to get in and out."

"I don't trust him."

"You don't trust either of us. Stop being childish, you know Kreacher can't disobey me and —" he looked down as the house elf muttered something insulting under his breath, and sighed. "Kreacher, please. Don't start."

He glared at Sirius, who glared back.

"So what's in there?" he asked.

"From what he told me, a lake full of Inferi. In the middle of it, there's an island with a basin filled with a potion. The Horcrux is inside."

Sirius looked warily at the water crashing on rocks below them. Inferi. Animated corpses. Their only weakness was fire, and in an environment with so much water…well, fire spells wouldn't last long here. He licked his lips nervously.

What if it was a trick? To lure Sirius away from allies and get rid of him? He knew Voldemort and many other Death Eaters thought of him as a nuisance on top of being a blood traitor. Maybe they had ordered Regulus do take care of it?

"We should have told someone from the Order before coming."

"We can't," Regulus insisted. They already talked about it before leaving, but the idea of going to the Order seemed to make Regulus more nervous than he already was. "If they know it might go back to the Dark Lord."

Sirius should have refused to go without another Order member. Regulus' distrust in them was both suspicious and understandable — he didn't know how they would react to his apparent defection or even his wish to take Sirius…wherever they were.

On another hand, who would go through all this trouble just to get rid of Sirius? Certainly not Regulus, anyway. He didn't work like this. If he wanted to get rid of Sirius, he would just stay out of sight and get him in the back.

Sirius called it the coward's way. Regulus called it the effective way.

"So, we just…get in, snatch the thing, and leave?"

"Not exactly."

Regulus pulled a locket out of his pocket. It was gaudy, very old-fashioned jewelry, and as far as Sirius was concerned, hideous.

"And this is…?"

"One of our family's heirlooms." No wonder it was so ugly. "It can pass as Slytherin's locket. The real thing was lost a while ago, but the Dark Lord tracked it down, made it one of his Horcruxes and put it in the cave. Once we take it, we replace it with the fake."

"And you honestly think he won't notice?"

"I don't know. At least it'll delay him, giving us some time to find the others before he realizes we stole it."

Sirius took a deep breath. He believed Regulus, but it didn't mean he was ready to follow him right into an Inferi den. If Regulus chose to go, then he wouldn't stop him, but Sirius wasn't in a hurry to get there.

But what if Regulus _died_?

He sighed. "Let's go then," he said and Regulus took a hold of his arm, then extended a hand to Kreacher, who took it.

Kreacher transported them inside.

It was dark and damp, and even colder than outside. Sirius looked around. They were at the centre of a lake, just like Kreacher at said, and a few meters away from them was a basin glowing a poisonous green.

"Well, it looks delicious."

"Stop trying to be funny."

"I'm hilarious."

Regulus rolled his eyes, but Sirius was sure he was smiling. He looked inside the bowl, and inside looked a little like Reg's. However, Sirius wasn't sure how long it would fool Voldemort. Still, he pointed his wand at the bowl.

" _Accio_ locket."

Nothing happened. Sirius then tried to vanish the potion, but it had no effect either. The both of them tried to part it, siphon it, or even evaporate it, but nothing seemed to word.

"Looks like we have to drink it," Regulus finally said, then he grimaced. "That's something he would do."

"I'm not drinking that."

"Don't worry, I will."

That stopped Sirius right in his track. "No," he said. "You won't."

"Yes, I will. First of all, your fire spells are probably more powerful than mine. Two, Kreacher is our ticket out and there's no way I'm putting him through this again. I'm the best choice."

"I'm not letting you do this, Reg."

Regulus narrowed his eyes at Sirius, looking miffed. "You can't tell me what to do."

Sirius scowled. Why did he have to be so difficult?

"Listen, Reg. Kreacher won't obey me, which means that if some shit happens, you're the one who'll have to order him around. We don't know what this potion does—"

"Tell him, Kreacher."

Sirius looked down at the house-elf, who sent him a disgusted look before complying.

"Kreacher had to drink the potion," he explained. "It burned Kreacher's insides and then, Kreacher saw terrible, terrible things— Kreacher was so thirsty, he crawled to the lake and —" he sent a fearful look the to water. "Hands, dead hands grabbed Kreacher and pulled him under the water! Kreacher was sure he was going to die, but Master Regulus called! Master Regulus saved Kreacher!"

That didn't sound good — but not as bad as Sirius imagined it. He had thought about torturous pain, vomiting blood, maybe not dying but damn close, the works.

"Okay," he said. "I'll do it. We need you coherent enough to get us out of there."

"I—"

"Don't pretend your fire spells aren't strong enough," Sirius cut while conjuring a goblet. "We fought before, and I know what you're capable off."

Regulus had been masked that day, but it took more that a mask to prevent Sirius from recognizing him. He knew him — his mannerism, his voice, the way he spoke when he cast spells.

He grimaced, knowing exactly what Sirius meant, and finally sighed.

"I don't like this."

"That's too bad," Sirius said. He plunged the goblet into the potion and downed it in one go.

It burned.

He stumbled, and Regulus caught him before he could fall. "Sirius!"

"I'm good! I'm good." He took a deep breath, and drank again. His insides were burning, and his head hurt. His knees buckled, and Regulus helped him sit down, kneeling next to him.

"Are you sure?"

"Yeah, fill it up."

Regulus took the goblet from his hand and filled it again. His hands shook as he handed it to Sirius, his eyebrows knitted together. He hesitated, and Sirius rolled his eyes. "Come on," he said. "What's with the face?"

"I don't want you to hurt yourself," Regulus admitted. 'I've seen what it does from Kreacher and I— I don't want to see you like this."

"Aww, didn't know you cared."

Regulus sent him a flat stare, his eyebrow twitched, and he pushed the goblet into Sirius' hands.

"Shut up and drink."

Sirius grinned, and took the goblet from Regulus' hand. He drank it again. Pain shot through his head and he closed his eyes.

He drank again, and again, and his vision blurred. Regulus' voice was distorted, but he was still talking to him — telling it would be okay, that he was here, that Moony hadn't forgiven him for the what he had done.

It wasn't a big surprise. Sirius had fucked up on an impressive scale and Moony would never, _never_ forgive him.

"I'm sorry, Moony…"

"What?"

"It's my fault…"

"Sirius, what are you talking about?"

Sirius would barely hear him. It was something was glowing in the corner of his eyes, and it felt warm, like a full moon night in the middle of spring.

Someone was holding him up, but he couldn't remember who — he could just see black hair and a pale face, it had to be James. Oh, Merlin, James…

"Prongs," he mumbled. "I'm sorry…I don't know what I was thinking."

 _"You think I don't know that? You never think, Sirius!"_

"I know, I know, I'm sorry— He kept poking his nose in it, and he knew there was something about the Willow, I never wanted Moony to—"

 _"Didn't want Moony to attack him? I don't believe it for a second. Your petty grudge on Snape almost got both of them killed! "_

"I'm sorry.…"

More liquid passed his lips, and his mouth went dry — it hurt, it hurt so much…

"Please stop," he managed to say, hands tightening around James. "Please James, stop—"

"It'll be over soon," James told him. "And James isn't here. Whoever you're seeing, it's not him."

It didn't make sense.

"What?"

"It's me, Reg. Regulus. Your…" A pause. "Your brother."

Regulus. What was Regulus doing here? It was past curfew and a full moon night, he needed to get back inside… He drank more, something pounded in his head and he was pretty sure he was sick with a fever.

"Reg—"

"Yes, I swear it's me."

Tears rolled down his face, and he could barely breath. Something inside of him was burning like Fiendfyre, and he needed it to stop.

"Please," he begged. "Please don't make me—"

"I've got to, Siri," James-no-Regulus said, and Sirius drank more.

"It burns, please don't."

"Everything is going to be fine."

 _"Make it stop!"_

A voice whispered in his ears — _drink_ , it said, _drinking will make it stop_. He finished the drink, and there was no more, but he was still in pain and his tongue felt like sandpaper.

"Water, " he croaked out.

Someone scrambled a little around him, and the goblet was pushed against his lips, but it was empty. He heard muttered curses, and Reg-or-James (he didn't know anymore) moved. Sirius tried to grab his sleeve.

"Don't…don't leave me…"

"I'm not, I'm just getting water."

Water splashed, and his companion yelled something. Light and heat erupted — fire, the Inferi had woken up, they needed to get the locket and—

The locket. Right.

He was thirsty and he couldn't move, but he could feel his mind clearing a little. He remembered why he was here — Regulus, the Hocruxes, the cave, the potion. Why had he volunteered for that potion again?

Reg's ability to give Kreacher orders.

Reg's safety. He couldn't let him drink it, he couldn't let him poison himself, no matter how much he insisted.

It didn't even make sense that Regulus would want to drink it. Normally, he would let Sirius do it as soon as he volunteered and called "self-preservation" but he hadn't, he tried to dissuade him — what the hell was he thinking?

The idiot.

His head was spinning as he pushed himself up and shoved his hand in the basin, feeling around the bottom until his fingers closed around the locket's chain. But, still dizzy, he fell again.

The goblet was shoved into his hand again. " _Drink_ ," Regulus hissed, and Sirius obeyed. This time cold water ran down his throat, calming the fire inside him and letting him think straight.

Inferi screeched and burned on the small island's ground, and the noise was making Sirius' head hurt. He stood and pulled his wand out.

" _Incendio_ "

Fire came out, burning the Inferi. Regulus turned to him, and Sirius offered him a weak grin. Reg smiled back, before his eyes widened as he fell, an Inferi pulling his ankle from under him.

"Shit!"

It dragged him towards the water, and Sirius ran towards him, snapping out a curse that cut off the Inferi's arm. He pulled Regulus closer.

"I got the locket."

"We need to get out of here." Regulus turned an incoming Inferi to crisps, and started to call Kreacher, who was cowering behind the basin. But before he could, Sirius felt something grab onto his pant leg and he tripped. "Sirius!"

The locket escaped Sirius' grasp and bounced on the stone. Regulus immediately went down to grab it, and but another Inferi came onto him and he tried to physically wrestle it off. The creature sank his teeth into Regulus' arm.

"Master Regulus!" Kreacher screeched. "Kreacher needs to take Master Regulus out of here!"

Sirius tried to pulled himself back on his feet, but the Inferius attached to his leg was dragging him towards the lake. He saw Regulus' eyes, wide and fearful, as he tried to get a hold of his arm but missed by a centimetre.

Then Sirius couldn't breath anymore.

Water surrounded him, the Inferi's nails dug into his skin as they pulled him deeper and deeper. He struggled to free himself, but they were stronger than him.

He couldn't see anything except some bright flashes of orange lights from above. Regulus was still here, why was he still here? Why wasn't he leaving? He had the locket, he didn't need Sirius anymore—

His lungs hurt and his vision blurred. His whole body felt heavy, he couldn't fight back anymore, and he instinctively breathed in — water rushed in his lungs. He choked.

Merlin, he was going to die. Regulus was going to leave him behind, right?

A spell whizzed right past him, and an Inferius' head popped of its shoulders. It didn't let go but another did the trick. Sirius' head was fuzzy, and everything was numbed by the cold, but he felt something pulling him up.

He was shoved on the wet rocks of the island, and coughed some water out. Regulus called for Kreacher in a surprisingly sharp voice.

"Get us out now!"

The cave disappeared and they fell on the path, gasping for air, at the exact place they had arrived earlier. The wind just made him colder, but at least he wasn't dead.

"Sirius?" Regulus mumbled, out of breath. He still held onto him so tight Sirius was pretty sure it cut his blood flow in his arm. "You okay?"

"I'm fine." His voice was raspy and he coughed more. He sent him a tired look. "You saved me. I thought—"

He didn't finish his sentence, Regulus threw himself at him and enveloped him into a tight hug. For a moment, Sirius was frozen, not knowing how to respond, then he wrapped his arms around his brother and hugged back.

He closed his eyes, breathing deeply, listening to Regulus' frantic heartbeat and savouring the fact that they were alive.

"You thought I was going to leave you here," Regulus whispered, his face buried in Sirius' chest. "I wouldn't. I couldn't—" he choked on the last words. "I can't lose you again."

"You won't," Sirius promised without thinking. "Also, I can't breath."

"Oh."

He let go, his face a little pink. Sirius' head started swimming again, accompanied by a particular strong wave of nausea. He bent over to throw up, and Regulus grimaced.

"You still look pretty bad. I'll apparate us back to your place, but before that… Kreacher!"

"Yes, Master Regulus?"

The voice grated at Sirius' ears. He shuddered, and wrapped his arms around himself. The cold was starting to get to him.

"Do we really need to take him with us?" he groaned, and glared at the elf.

"We aren't."

He blinked. Regulus didn't look too happy with Kreacher. He was scowling at him, weighing his options. Then, he pushed himself to his feet and pointed his wand at the elf.

" _Obliviate_ ," he snapped. Kreacher's ugly face went blank. "Go back at Grimmauld Place and don't tell anyone you were out today, Kreacher."

"Yes, Master Regulus."

He disappeared with a pop.

"What—"

"I'll explain later," Regulus said shortly, before pulling Sirius up. He stumbled, and Regulus just put one of his arms around his shoulder. "Just hold onto me and brace yourself. This isn't going to feel nice."

Sirius nodded, and Regulus apparated them right into his living room.

He threw up all over the floor.

"Oh dear," Regulus muttered before guiding Sirius to the couch and helping him lie down.

He vanished it quickly. Then, he opened the closest cupboard and started rummaging in it.

"What are you doing?"

"Looking for Pepperup," Regulus answered. He yawned. "We just took a bath in freezing water, I'm not taking any chances, especially since you thought it was a good idea to _poison yourself_."

"You were going to do it, you can't criticize me."

"I'll criticize you all I want."

Sirius hummed in disagreement, but still took the potion Regulus gave him. "Why were you so mad at Kreacher?" he asked.

Regulus didn't answer immediately, instead he stared at him for a long few seconds, mouth tilting downward in a grimace.

"He wanted me to leave you. You didn't hear because you were underwater, but he said that we should leave you and…I'm not even surprised he suggested it. He's my friend, and I obliviated him to protect him but—"

 _I can't lose you again._

Sirius didn't say anything immediately, looking straight at his brother. Then, he snorted. His hair was a wet mess of curls and knots, his face was dirty and—

"You're bleeding," Sirius noted, frowning.

"Uhm?" He looked down at the wound on his arm. "One of them bit me."

Dread creeped into Sirius' stomach. Bitten.

"He could have been bitten!"

It was his fault, he shouldn't have told Snape how to get past the Whomping Willow, now Remus was going to get in trouble and he was going to die and it was all his fault—

He squeezed his eyes shut and shook his head.

"Not real," he muttered. "Sorry."

"It's okay." Sirius could tell he wanted to ask, but he didn't. Instead, he stood. "I'm just going to clean up."

Sirius nodded reluctantly. He didn't know if it was the fever, or the almost dying, or the poisoning, but he didn't want to be alone right now.

It was strange. It wasn't the first time Sirius had come close to dying. He had been in several battles and sat for his NEWTs, for Merlin's sake. Today was different.

In the heat of the battle, with James and Lily and Remus and Peter by his sides, he always felt almost immortal.

Today he had willingly drank poison and would have drowned scared and alone if it hadn't been for Regulus.

He yawned. His eyes were closing by themselves and soon he fell asleep, so he didn't hear Regulus come back to check on him.

* * *

The next day he was still feeling a little queasy. Regulus was curled up at the other end of the couch, still sleeping. When Sirius moved, Regulus eyes shot open and he quickly sat, looking around wildly.

Light sleeper, of course. They better be when Voldemort himself might knock at their door.

"How are you feeling?" Regulus asked.

"Better. So, we have the locket, now what?"

"I've been thinking about what the other Horcruxes could be. Maybe objects passed down the Slytherin line?"

"Do you know of any?"

His face meant no. Sirius sighed. Sure, they had the locket, but it didn't look like they were going to make anymore progress.

"I need to be more awake for this. Do you want some coffee?"

"What's coffee?"

Sirius gaped at him, dumbfounded.

"Stay here," he ordered. "I'll make up for the gross injustice done to you, Reggie."

Regulus blinked at him, and Sirius left the room in a hurry. What's coffee? Honestly, sometimes Sirius wondered how anyone survived without it, and Regulus didn't even know about the Merlin blessed drink.

He quickly poured two mugs of coffee and handed one to Regulus when he went back to the living room. Regulus took a sip and wrinkled his nose.

"It's…very bitter."

"You learn to like it." He drank some of his and sighed in contentment, before going back to their previous conversation. "You said he asked for a house-elf. Did you volunteer Kreacher? Or did he ask you personally?"

"I volunteered," Regulus answered. "But he still asked a Death Eater for…help, sort of." He frowned. "Now that you mention it, I can't be the only one he asked. We need to figure out who else—"

"Why did you volunteer?"

Regulus stopped, face suddenly blank.

"I—" He hesitated and put his mug down. "I wanted to prove that I was loyal to him," he said with a sigh. "Because whether you like it or not, we're brothers and due to our relation, the Dark Lord — no, everyone — doubted me. I just wanted to… I wanted to prove them wrong, you know? To prove them and myself that I was good enough." He smiled wryly. "See how well that worked out."

Considering they were having one of their first civil conversation in four years, Sirius would say it worked out pretty well. He didn't say it out loud, choosing other words instead.

"And you chose to betray him and to do what you thought was right," he said, and Regulus nodded slowly, still not looking at him. "It's not just being 'good enough' it's being better."

"If you say so."

Sirius rolled his eyes. "Look at me." When Regulus did, he went on. "It would've been so damn easy to just go along with it and never ask questions. You didn't, Reg. You fucked up, badly. There's no denying it, but you're trying to fix it and that's…that's _good_."

"It's not 'good', it's common sense."

Merlin, Sirius was so bad at this. He wasn't used to…making people feel better and all that.

He was usually the one who tried to make people laugh so they would forget their trouble, not the one who gave deep speeches or whatever. That was what Moony did.

He needed to be more than that, because less than two days ago, Reg's whole world had collapsed and he was vulnerable and struggling to keep himself together. Right now he needed Sirius, and he needed to feel safe.

"It's not as common as it sounds. I know, because I don't have much of it. Or so Lily says."

Regulus snorted. Point to Sirius.

"But you never messed up that bad, right?"

"I did. Well, I didn't join a cult advocating for Muggleborn extermination but I did some stuff I'm not proud of." What he had done to Moony was first on the list. "You're dealing with your mess better than I did." He stopped, considering his next words. "I guess, what I'm trying to say here, is that I'm proud of you."

It sounded a little out of character for him to say it. He had never told Regulus he was proud of him — not even when they still got along.

It had taken him longer to see through the bullshit their parents always fed them, but he was finally here. Sirius had his little brother back.

* * *

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 _See you~_


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